Cable-braking apparatus



Sept. 4, 1962 A. s. AVIS CABLE-BRAKING APPARATUS 4 Sheets-Sheet l Filed July 19, 1961 Sept. 4, 1962 A. s. Avis 3,052,426

CABLE-BRAKING APPARATUS Filed July 19, 1961 4 Sheets-Sheet 2 Sept. 4, 1962 A. s. Avis cABLE-BRAXING APPARATUS 4 Sheets-Sheet 5 Filed July 19, 1961 Wm di KMJ m #uw /m fmwn# A Sept. 4, 1962 A. s. Avis cABLE-BRAKING APPARATUS 4 Sheets-Sheet 4 Filed July 19, 1961 lice s Patented Sent= 4i, i352 3,052,426 CABLE-BRAKHNG APPARATUS Arthnr Stnniey Avis, Ashford, Engiand, assignor to Viciters-Armstrongs (Aircraft) Limited, London, Eng tand, a british company Filed duly it?, wel, Ser, No. 1252i@ Claims priority, application Great Britain Joly 2l, i964) 7 Ciaims. (Cl. 242-itl7.3)

This invention has reference to apparatus for use in lowering a load by means of a cable payed out from a winch or the like, the object being to provide means whereby the speed of lowering may be controlled at a desired rate, and for the rewinding of the cable after use. A further object is to provide means whereby a load may be partially supported when, during the operation of raising the load manually, the lifting effort is momentarily relaxed.

Apparatus for the purpose stated comprises `a helically grooved drum upon which the cable connection with the load may be wound, said drum being adapted to be driven for rewinding the cable by a spring motor which is energised by the reverse rotation of its driving element when the load is payed out, and a friction brake unit Which is automatically clutched to `a stationary part of the apparatus when the load is payed out and released when the cable is rewound. rIhe apparatus is preferably enclosed in a casing having an aperture for passage of the cable therethrough to and from the drum, the drum being splined upon the driving element of the spring motor for axial movement in the casing so that the point at which the cable enters or leaves the helical groove of the drum remains opposite said aperture at all times.

The manner in which the invention may be carried into efect is hereinafter described in greater detail with reference to the accompanying drawings. In said drawings FIG. l is a perspective view of part of the interior of a stowage compartment eg. of an aeroplane, illustrating the use of the supporting and lowering apparatus provided by the present invention for the suspension of a load'. FIG. 2 is a partly sectional elevation of the supporting and lowering apparatus shown separately, and FIGS. 3 and 4 are transverse sections taken respectively on the lines lli-Jil, and IV`IV, of FiG. 2.

it may be seen from FIG. l that the invention is concerned with the provision of means for supporting a load A within the stowage compartment of which the ceiling and one wall are respectively indicated at B and C. Such means as provided by the invention takes the form in this embodiment of the apparatus, indicated in FIG. l generally by the reference letter D, which is illustrated in detail in FIGS. 2 to 4. Cables for the suspension of the load A at its opposite ends are payed out from the apparatus D, one such cable extending vertically downwards and 'the other being passed over a guide-pulley E.

Referring now to FlGS. 2 to 4 of the drawings, it will be seen that the apparatus D is enclosed in a casing which is conveniently fashioned in two cylindrical complementary sections lill and ZttiZ having abutting anges liull and Mill which are bolted together at N3. Mounted rotatably within the inner cylindrical bore provided `by the combined' inner walls of the two casing sections lill, im is a drum il having an external peripheral helical groove ill in wh'ch are laid the two cables previously referred to and here designated by the reference numerals l2 and 13. At one end the cables are attached to the drum and their other ends emerge from the casing through holes of which one is shown at 3l. In order that the point at which each cable leaves the drum groove lll may remain opposite the relative aperture at all times, the casing section itil is provided with a peg i4 which projects inwardly to engage the groove lll, in such manner that as the drum il is rotated by the payingout or winding in of the cables it is constrained by the cooperation of the peg with the groove to move axially within the casing.

A dise l5 is splined within the drum il and arranged to lie flush against the adjacent face of a plate l5 which is provided with an axial boss which is rotatably mounted upon a stud journal i7 mounted on the inner endwall of the casing section itil. An enlarged part i71 of the stud i7 is bored to tit upon a hub 1912 which projects axially inward from the casing section lili, and a hexagonal-section plug 13 is received in conformably shaped sockets in the stud 17 and hub itilZ to prevent rotation of the former relative to the latter. Mounted upon the disc i5 in equiangular spacing about its axis are a plurality of screws 19 each of which carries two aligned rotatable spools 2t), 2i, and each such spool has Wound thereon a flat torsion spring 22 the end of which is anchored at 23 to one of the faces or" the polygonal-section part 171 of the stud ff'. The arrangement is such that when the cables l2, i3 are payed out to lower the load, the disc ld rotates with the drum l1 in relation to the member 171 and the several springs 22 are unwound from their spools and wound in the opposite sense in snperposed relation upon the member 3.7i. When the load is removed from the cables at the end of the lo'vveriw7 operation, the energy stored in the springs 22 drives the disc l5, causing the drum 11 to be rotated in the reverse direction, and as the springs 22'. are re-wound upon their spools the cables l2, 13 are re-wound in the groove ill of the drum il.

rIlle lowering operation is controlled, and a load is partially supported, by a friction brake unit which is applied to the drum. A single clutch plate 24, splined at its periphery within the drum il so as to be driven by the rotation thereof, is mounted between two stationary friction elements 25' and 26 which are respectively carried by the plate i6 and an annular member Z7 which is attached by screws 272i to the face of said plate lo remote from the disc l5. A pressure plate 2S splined on the member 27 is arranged to impart pressure through an assembly of coiled springs 29 to the friction element 2o so that the clutch plate 24 and the two friction elements 25, 26 are compressed and, through the driving connection between the clutch plate 2li andthe drum il, the rotation of the latter is retarded. The outer ends of the springs 29 are received in a recessed annulus 35i which is slidable on the member 7.7 and is adapted to be adjusted thereon by a nut 3l which is threaded on an axial extension 272, of the member 27, rotation of said nut being effective to vary the pressure of all the springs 29 collectively.

The member 27 is counter-bored throughout part of its axial length to receive a spigot 32 which is attached to the casing section 102. The combined bores of the member 27 and said spigot 32 are used to house a rectangular close wound helical spring 33, hereinafter referred to as the locking spring, which is an interference t in said bores yand the end of which is anchored at 331 in an internal sleeve 34 which is rotatable in the casing section 162, the arrangement being such that on rotation of the clutch plate 24 with the drum il when the cables i2, 13 are payed out, a braking force is applied to the clutch plate by the fact that the member 27 is clutched thereto by its rotation against the lay of the locking spring 33. When the clutch plate 24 is rotated in the opposite direction the locking action of the locking spring 33 is neutralised by the clutch assembly rotating with the lay thereof.

The sleeve 34 may be partially rotated with the aid spaanse of a tommy-bar passed through the holes 3411, in the direction of the lay of the spring 33 to permit the easy withdrawal of the cables, if required, lby freeing the annultus 27 yfrom the spring 3S temporarily.

What I claim as my invention and desire to secure by Letters Patent is:

`1. Apparatus, capable of use for paying-out and rewinding load-connected cables, comprising: a helicallygrooved drum, arranged for rotation and for limited translation in directions along its axis of rotation; at least one cable laying in the drums helical groove thereby defining a helical cable Winding about the drum, one end of the cable being anchored to the drum, the other end of the cable having means for its connection to a load; con- `trol means; friction braking means automatically controlled, by said control means, for retarding the rotation of the drum when rotating in a direction to play-out said cable, and for not retarding the drums rotation when rotating in a direction to rewind said cable about the drum; spring motor means, including a driving element coupled with the drum, for rotating the drum in a direction to rewind said cable, said driving element energizing said spring motor means as the drum is rotating in a direction to pay-out the cable; and, a casing, having at least one laperture therethrough, enclosing at least the drum, the aperture allowing passage of the cable to and from the drum, said casing including a lixed abutment arranged with the drums groove to effect translation along the axis of rotation of the drum as the drum rotates whereby the point on said groove at which the cable is payed out, or rewound, always remains opposite said aperture.

2. Apparatus as detined by claim 1, wherein the spring motor means comprises a disc-like driving element splined in the drum for rotation therewith, an axially disposed txed member mounted on the disc-like driving element, a plurality of spools mounted on said disc-like element, each spool having a torsion spring wound thereon with the end of the spring anchored to the axially disposed xed member, the arrangement being such that when the cable is payed out the rotation of the disc-like element is effective to unwind the springs from the spools and to wind them upon said xed member in the opposite sense,

the energy thus stored in said springs serving to drive the disc-like element and drum in the reversed direction when the load is removed.

3. Apparatus as deiined by claim 2, wherein the spools are disposed in equiangular spacing about the axis of the disc-like element and so arranged that the springs are rewound upon the tixed member in superposed relation.

4. Apparatus as deined by claim 1, wherein the fric tion braking means comprises a clutch plate fastened to the drum, a support member arranged within the casing, two friction elements mounted on the support member, the clutch plate being situated between the two friction elements, and an assembly of compression springs mounted on the support member and arranged for cornpressing the friction elements against said clutch plate.

5. Apparatus as dened by claim 4, wherein said support is an annulus mounted within the casing co-axially with the drum, and wherein the compression springs are disposed between two pressure plates splined upon an outer surface of said annulus, one of said plates being adjustable on the annulus in an axial direction for variation of the etective pressure of the springs on the friction elements.

6. Apparatus as defined by claim 1, wherein the automatic control means comprises a close wound rectangular-section helical locking spring so coupled with the friction braking means whereby rotation of the drurn in the cable pay-out direction is retarded by the lay of the wound spring relative to the braking means and rotation of drum in the rewind direction is not retarded by the lay of the wound spring relative to the braking means.

7. Apparatus as defined by claim 6, wherein said automatic control means comprises additional means for temporarily uncoupling said locking spring and braking means.

References Cited in the tile of this patent UNITED STATES PATENTS 2,546,202 Trouin Mar. 27, 1951 2,594,484 Nixon Apr. 29, 1952 2,659,573 Smith Nov. 17, 1953 2,791,397 Coffman May 7, 1957 2,990,131 Carlsson June 27, 1961 

